RT info:eu-repo/semantics/article
T1 Local carrier PWM for modular multilevel converters with distributed PV cells and circulating current reduction
A1 Al-Jawary, Zaid A. H.
A1 Pablo Gómez, Santiago de
A1 Herrero de Lucas, Luis Carlos
A1 Martínez Rodrigo, Fernando
K1 Tecnología
K1 Electrónica
K1 Pulse width modulation
K1 Modular multilevel converter
K1 Photovoltaic power systems
K1 Modulación de ancho de pulso
K1 Convertidor multinivel modular
K1 Sistemas de energía fotovoltaica
K1 3307 Tecnología Electrónica
AB A new topology has been recently proposed for grid-connected photovoltaic (PV) systems, using modular multilevel converters (MMCs) and distributing PV panels throughout the MMC cells. This topology has two main advantages: it reduces the power losses related to moving the energy into the MMC capacitors from an external source, and it removes the losses and costs related to the DC to DC converters used to track the maximum power point on string converters or central converters, because that task is delegated to MMC cells. However, traditional pulse width modulation (PWM) techniques have many problems when dealing with this application: the distortion at the output increases to unacceptable values when MMC cells target different voltages. This paper proposes a new modulation technique for MMCs with different cell voltages, taking into account the measured cell voltages to generate switching sequences with more accurate timing. It also adapts the modulator sampling period to improve the transitions from level to level, an important issue to reduce the internal circulating currents. The proposed modulation has been validated using simulations that show a consistent behavior in the output distortion throughout a wide operation range, and it also reduces the circulating currents and cuts the conduction losses by half. The behavior of this new topology and this new modulation has been compared to the mainstream topology with external PV panels and also to a fixed carrier modulation.
PB MDPI
YR 2020
FD 2020
LK https://uvadoc.uva.es/handle/10324/58738
UL https://uvadoc.uva.es/handle/10324/58738
LA eng
NO Energies 2020, vol.13, n. 21, 5585
NO Producción Científica
DS UVaDOC
RD 22-dic-2024